These posts have definitely helped me refine and revise my own ideas!
1) Sunita revises my original thesis in important ways by talking about how historical worldbuilding might differ from SFF worldbuilding. I agree! The register in which historical worldbuilding happens is generally more constrained in important ways. Again, I want to highlight the idea (as I should have done more effectively in my original post) that historicity is predicated on how facts get employed--and also how they get bent--and what kinds of facts are ripe for bending in the first place.
One question that I'm pondering has to do with why we would never ever mistake a Historical romance for a document of the period, fictive or non...
2) ...which brings me to the divine Sarah, who writes that romances to me are about the way people THINK and .
She points out (crucially) I think, that our contemporary ideas about self/identity/romance evolved out of eighteenth century discourses of ideas--as did the psychological novel in the west! (Lady Murasaki's Tale of Genji is often cited as the first real psychological novel but it doesn't get Englished 'til the 20th century.) I hadn't thought of it in so many words before but, to write a psychological novel about an historical period pre-dating the eighteenth century is already indulging in a kind of creative anachronism.
This insight really helps me think about very rich, variegated historical worldbuilding in novels that depict, say, the early modern period. I'm thinking particularly here of stuff like Dorothy Dunnett's inimitable Lymond Chronicles and Mary Renault's The Last of the Wine which, although beautifully, exhaustively researched and dense with detail, seem to me very idionsyncratic and highly personal views of what sixteenth century Europe or Classical Athens were "about."